Radio receiving set



T. J. SCOFIELD Er AL April 17, 1934.

RADIO RECEIVING SET I 2 Sheets-Sheet l W ITORNEY Filed Oct. 50, 1929 April 1934- 'r. J. SCOFIELD ETAL 1,955,150

RADIO RECEIVING SET Filed Oct. 30. 1929 2 Sheets-Sheet 2 MY/m INVENTOR BY Z MW & A ORNEY Patented Apr. 17, 1934 RADIO aeoarvmo sa'r Theodore J. Scoileld and William D. Miner, Jackson, Mich, assignors, by mesne assignments, to Radio Corporation of America, New York, N. Y., a corporation of Delaware 1 Application October 3051929, Serial No. 403,530

Claim.

This invention relates to radio receiving sets. One of the objects of the invention is the an ranging of a large number of parts of a radio set in separate unit s, two of which are shown with 5 quick connecting means therebetween so that they may be readily assembled and disassembled without manipulation of any binding screws.

Another object is to construct a novel form of anchor for the stator plates in combination with a so-called trimming condenser, the parts being so arranged so that the condenser may be readily adjusted without removing the cover of the unit in which it is placed.

Other objects will appear in the appended description, reference being had to the drawings in which:

Fig. l is a side view of the tuner unit and the amplifier unit with a quick connecting means making connection between the two units.

Fig. 2 is a view of the antenna condenser, antenna binding post and ground post as viewed from the right of Fig. 1.

Fig. 3 is a plan view of the spring clamping connection of the amplifier unit adapted to receive the pin of the tuner unit,'as shown in Fig. 1.

Fig. 4 is a longitudinal section of the spring connector shown in Fig. 3.

Fig. 5 is a partial sectional view of the connecting pin adapted to function with the spring connector of Fig. 3.

Fig. 6 is atop view of the anchor for the stator plates shown in Fig. 1.

Fig. 7 is a plan view of a pair of condenser plates of the trimming condenser shown in Fig. 1.

Fig. 8 is a perspective view of the cover plate adapted to fit over the tuner unit shown in Fig. 1, certain of the screw parts of the tuner unit being shown-in proper relation to certain openings in the cover.

Fig. 9 is a view of the sleeve for the rotor plates shown in Fig. 1.

Fig. 10 is an enlarged end view of the sleeve shown in Fig. 9, the condenser shaft being shown in section.

Fig. 11 is an enlarged view of a modified form of sleeve.

Fig. 12 is a plan view of the antenna condenser shown in Fig. 2.

Fig. 13 is an end view of a portion of the amplifier unit housing as viewed from the left of Fig. 1.

Fig. 14 is a perspective view of the supporting angle for the antenna condenser shown in Figs. 2 and 12.

Radio receiving sets are usually made with a plurality of radio frequency amplifying tubes, a detector and one or more audio amplifying tubes. In some cases the amplifying tubes have the grid circuits connected to tuning condensers and in other cases neither the grid nor the plate circuits of the radio frequency tubes are tuned. Selectivity in this latter case is obtained by tuning a plurality of circuits through which the signal passes before it reaches the amplifying tubes. Our invention is applicable to either of these two types or to anyother type where tuning and amplification is involved.

The condensers for tuning the radio set, regardless of the type, consistof rotor plates 1 adapted to interleave with stator plates 2. The number of these pairs of rotor and stator plates depends upon the number of tuned stages, but by way of example, we have shown four, all being constructed similarly. The four bushings 4 holding the rotor plates are properly spaced on rotatable shaft 5, which in turn is secured to drum 6 of any construction, but preferably of the construction shown in the application of T. J. Scofield and W. D. Miner Serial No. 398,864, filed October 11, 1929.

The rotor bushing or sleeve 4 is sawed or otherwise notched at 3 to receive the rotor plates. Each bushing is centered on the shaft 5 by broached ridges 7, 8 and 11 with set screws taking up whatever slack there is between the two parts. In the modification of Fig. 10 the ridge 11 is omitted. This form of rotor mounting very correctly aligns the rotor plate bushing with the slots 3 perpendicular to the axis of the shaft and we therefore prefer to use it in our invention.

The stator plates 2 are soldered or otherwise fastened into slots 12 of an anchor 13, shown in plan in Fig. 6. This anchor plate consists of a brass or other good conducting metallic stamping bent into a general right angle form, The horizontal portion of the plate 13 has a central hole 14 adapted to receive-an adjusting screw 15 of the trimming condenser, the horizontal portion forming one plate of such condenser, as will be later described.

The stator plates positioned on the anchors 13 are aligned in proper position and fastened by appropriate screws or other connections 16 to an insulating strip 1'1 secured to the end portions 18 and 19 of the frame of the condenser. The stator plates 2 are fastened to anchor plates on each side and the anchor plate opposite the one shown in Fig. 1 of each pair is connected to an insulation strip similar to strip 17, and such strip is similarly connected to the end plates 18 and zontal plate of the anchor 13 previously referred shown in Fig. 8 such a cover.

to, and the ends of a strip 2(lfastened to a bracket '21 secured to the metal chassis. The strips or plates 20 are made of good conducting spring material and form the other plates of the trimming condensers.

Mica or other insulating strips 22 are placed.

between the two plates of the trimming condenser, and are riveted between the strips and the brackets 21 This is merely to rigidly position the mica. The strips are conductively connected to the brackets 21 by the rivets-21".. The mica strip has a hole adapted to receive the adjusting screws 15. The screws 15 are threaded into holes 14 of the horizontal portion of the anchor plate and are held firmly in position by lock washer-24 or by other appropriate means. This arrangement insures that the adjusting screw will be held rigidly perpendicular to the condenser-plates. The hole 23 in the upper condenser plates (see Fig. 7) is made considerably larger than the adjusting screw and between the adjusting nut 25 and the upper plate is placed an insulating washer 26. This appropriately insulates the upper plate from the lower plate in each trimming condenser.

It is preferable to place a cover over the tuner unit for shielding purposes and to prevent injury to the rotor and stator plates, and we have This cover has screw holes 27 adapted to line up with holes 28 in the end plates of' the tuner unit and appropriate screws are threaded through the holes 27 and into the holes 28 to hold the cover in position. When the cover is thus placed in position the adjusting nuts 25. will be opposite slots 29 so that an adjusting wrench may be inserted with the cover in position to turn the nut of screw 15 to bring the upper condenser plate nearer to or farther away from the lower plate and thus obtain the right value of capacity in the adjusting nut 25 can be threaded to compress the upper, trimming condenser plate, or to relieve such compression, without distorting the alignment of screw 15 as that screw is threaded into the bottom plate 'and held firmly in position by the lock washer 24. This construction permits ease of adjustment of the trimming condenser at the factory or byservice men in the field without disturbing any of the other parts "of the tuner and without removing the cover.

Since only three trimming condensers are nec-' essary in the tunerfelement the plate 20 ofthe fourth trimming condenser is made single instead ofdouble.

on the upper part of the end 18 of the tuner element is arranged bracket 31 holding insulation plate 32. On this insulation plate is arranged lower plate 33 having an extension 34 adapted to make contact with'the antenna bind- The ing post 35. If desired the end part 34 may be made separate from the plate 33 and clamped 33 by means of an adjusting screw 39 which passes through an insulation washer 40, both condenser plates, and the mica strips, and is threaded into a metallic bushing, not shown, se-

cured in the insulation plate 32. The hole in the plate 37, and also that in plate 33, is made considerably larger than the screw 39 to prevent contact with the plate or plates, as the case may be. This condenser is the small trimming condenser for the antenna and the proper value of the capacity is obtained by adjusting screw 39 to bend the upper plate either towards or from the lower plate.

'The spring of binding post 35 is not shown so as to illustrate the shape of the metal clamping plate of this binding post. The binding post 41 is out of electrical contact with all metallic parts except anchor plate 31, which is, of course, in contact with the frame of the condenser. The metal plate of this binding post is similar to the plate on binding post 35 and has a hole in it, as shown, for the insertion of the ground,

wire of the receiving set. The plate is pressed upward against the tension of spring 42 so as to show this connecting hole. When the wire is inserted in the hole and pressure is relieved against the lower part of the plate, spring 42 will press the upper portion of the plate firmly against the ground wire. The ground wire will be held against the insulation plate 32, but of course it will make contact with'the plate 41 and thus be grounded directly to anchor plate 31 through spring 42.

By cutting out the lower portion of the plates 35 and 41 of'thebinding posts, as shown in Fig. 2, these plates can be readily inserted in the slots in insulation strip 32 and in the plates 33 and 31. The springs 42 can then be threaded on to the lower part of the plates over the projections on the ends. The supporting anchor plate 31 (see Fig. 14) has a slot 42' on one end to receive the binding post plate 41. Screws '43 clamp the insulation plate 32 to the anchor plate 31. By removing these two screws the condenser unit may be removed from the anchor plate 31 by sliding the assembled condenser to the right to free the anchor plate 41 from the slot 42'.

The tuner unit shown at the right of Fig. 1 has two terminals 43 and 44., The terminal 43 is connected to the condenser plate 37 of the antenna condenser, and the other terminal 44 is 'connected to connecting pin 45. Pin 45 is the tuner terminal that is to be connected to the grid of the amplifier.

Pin 45 is shown more in detail in Fig. 5 and consists of a long slender rod of good conducting material and proper rigidity. The end 46 of this pin is preferably larger than the other portion and has either a screw or rivet connection with insulation plate 47 which is secured to the end flange 48 by appropriate screws 49. A terminal link 50 is preferably riveted with the projection 46 to the plate 47 .and the lead 44 is soldered thereon. The supporting plate 48 is appropriately notched to .permit the lead 44 to pass through the hole 51 to the connecting plate 50.

Supporting plate 52 similar to the plate 48 cooperates with the latter plate to support the tuner unit on the base plate 53.' These plates 48 and 52 may be attached to the base plate 53 by appropriate screws 54. 1'

The amplifier unit is generally indicated by reference character 55 and consists of a metallic box or housing with metallic cover 56 housing vacuum tubes, six being shown in dotted lines. These tubes are secured in sockets 67 on base plate 57 and in any desired way. The bottom 57 of the amplifier housing has bolts 58, 59, adapted to clamp the amplifier unit to the base 53. When the amplifier unit is to be inserted into position in the radio receiving set it is placed in position on the base 53 in the cabinet with the bolts sliding into the ends of slots 60, 61. These slots are made of such dimensions as to permit their insertion with the end of the amplifier housing clearing the end of connecting pin 45. Also, in inserting the amplifier housing it may be tilted somewhat so as to help clear the pin 45. After the amplifier unit has been placed in position with the bolts 58, 59 through the slots in the base 53 the unit is slid toward the right in Fig. 1 and the pin 45 will enter into good contact with spring binding post generally indicated by reference character 62. A plan view of this spring binding post is assembled from the insulating supporting base 63in Fig. 3. The binding post is also shown in longitudinal section in Fig. 4. In these figures. the plate 64 has holes 65 in its ends to receive rivets 66" for clamping the post I to the insulating base supporting the vacuum tube receptacles 6'7 and other parts. The plate 64 is preferably stamped out of sheet'materi al with lugs that may be bent up to form ears 67, 68. These ears have holes 69 adapted to receive the pin 45. A spring wire 68'" is bent as shown in Fig. 4. 'One end of the springis free and the other one is coiled around one of the rivets 66 and clamped in position by that rivet. When the amplifier unit is slid to the right as previously described the point 70 on pin 45 will'slide under spring 68' and force the spring wire upward as it slides through the ears 67, 6B. This spring wire thus presses downward against the pin and maintains the pin in contact with itself and with the two ears of the plate.

In assembling the tuner unit and the amplifier unit the amplifier unit may be first assembled on a base 53 and the tuner unit slid to the left to insert the pin in the spring binding post and -the screws 54 may then be inserted to hold 'the tuner in position. I

The A, B and C current supply terminals and all the remaining terminals of the amplifier unit are contained in fabric tubing or loom 71 and led out through a slot'72 at the base of the housing of the amplifier unit shown clearly in Fig. 13. This slot has an enlarged portion 73 to permit the enclosing sheath 71 to pass freely therethrough. The various terminals of the amplifier unit led out through the hole 73 and slot 72 are attached to the various terminals of the amplifier unit inside the housing and the outer end of these conductors are fannedout through various portions of the outer end of the enclosing sheath 71 and are soldered or clamped-to individual con- .nectors 74. These connectors are to be screwed 53 inserted in the cabinet of the receiving set.

clips or connectors 74 to the powerimit and will remove the nuts of bolts 58 and 59. These can be readily reached at the back "of the cabinet. The amplifier unit then may be lifted out of the cabinet by sliding to the left and in some cases by tilting the left-hand end of. the amplifier unit upward until the unit is disconnected from the pin 45. A new unit can then be inserted by the service man and connections made in the 'reverse order.

If trouble develops in the tuner unit that unit may be taken out by removing screws 54 that hold the unit to the base 53 and by pressing upward on plates 35 and 41 to release the antenna and ground connectors. This unit may be then removed by sliding it to the right until pin 45 clears the amplifier unit and in inserting a new unit it may be slid to the left and screwed into position. 7

Service men will keep a supply of amplifier units and tuner units and whenever trouble develops in receiving sets in use a receiving set may be placed in perfect condition by insertion of a new unit in place of the defective one. All this requires but a few moments and the use of a receiving set is practically interrupted only the length of time it takes to get a service man on the ground. Thefisubject matter'relating to the antenna: condenser itself is not claimed herein but is claimed in our divisional case Serial No. 590,834 filed February 4, v1932.

Having described our invention, what we claim is:

1. In rotary condensers, an anchor consisting of two plates extending at right angles to each other, one of said plates being slitted and adapted to receive stator plates of .a condenser, and the other plate being a projecting shelf adapted to form one plate of another condenser, insulating means on said shelf, a spring plate on said insulating means forming the other plate of said other condenser, a screw threaded through the projecting shelf and held in rigid relation therewith, insulating means on said spring plate, an adjusting nut on said screw resting on said second mentioned insulating means to vary the capacity of the second mentioned condenser.

2. In a rotary condenser, a conducting frame, an anchor having sides at right angles to each other, insulatingly mounted on said frame, spaced stator plates secured to and supported by one of said sides of the anchor, spacedv rotor plates conductiveiy mounted on said frame and adapted to be moved between the stator plates, an auxiliary plate conductiveiy mounted on said frame and spaced from the other-of said sides of the anchor and means to varythe spacing between the auxiliary plate and said other side of the anchor to form a trimming condenser in parallel to that formed by the said rotor and stator plates.

3. In rotary condensers, a conducting chassis having end plates joined by conducting side bars, insulating strips extending across between said end plates; spaced angle bars having stator anchors and condenser plates extending at right angles to each other, a conducting bracket between the angle bars mounted on said side bars, a metallic strip conductiveiy mounted at its center on said bracket and having its ends extending over the condenser plates, and means toadiust said ends towards and from said condenser plates.

4. In rotary condensers, a frame, an insulation strip attached to said frame, a pair of anchors on said strip, each having a projecting shelf,

strip attached to said frame, a pair of anchors on said strip, each having a projecting shelf, stator plates supported on said anchors, rotor plates conductively supported by said frame and interleaving with said stator plates, a conducting support located between said shelves and conductively attachedto said frame, a conducting strip attached to said support and having its ends extending over said shelves, and means to independently move the ends of said strip to vary the spacing between the shelves and the ends of the conducting strip.

. THEODORE J. SCOFIELD.

WILLIAM D. MINER. 

